1. Department of Periodontics and Preventive Dentistry, School of Dental Medicine University of Pittsburgh Pittsburgh Pennsylvania USA
2. College of Medicine California Northstate University Elk Grove California USA
3. Department of Orthopaedic Surgery, Orthopaedic Trauma Institute, School of Medicine, Zuckerberg San Francisco General Hospital University of California San Francisco San Francisco California USA
4. Department of Medicine, Division of Rheumatology San Francisco VA Health Care System San Francisco California USA